Process of drying grain.



L. J. DENNIS.

PBOGESS OF DRYING GRAIN.

APPLICATION FILED NOV. 23, 1912.

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rnoonss 0P DRYING GRAIN.

APPLICATION FILED NOV. 23, 1912; 1,058,291 Patented Apr. 8, 1913.

' 2 SHEETE-SHEET 2.

WITNESSES INVENTOR g /ZWM .citizen of the United States LEE .1. nnmus,or uEMrn-Is, 'rnimnssm.

' rnocnss or ravine GRAIN.

Specification of Letters Patent.

Patented Apr. 8, 191-3.

Application filed November 28,1912. Serial 80.158580.

To all wiwm it may concern:

Be it known that I, Lnn J. Drums, 9. residing at Memphis, in the countyof Shelby and State of Tennessee, have invented certain new and usefulImprovements in Processes of Drying Grain, of which the following is aspecification.

This invention relates to the art of properly conditioning grain forstorage or shipment in bulk without deterioration.

The object of the invention is to accomplish this result at a-costgreatly reduced over that incident to methods that have heretofore beenemployed, and also to accomplish the result not only without developingin the grain objectionable conditions which have been incident toprocesses heretofore employed, but with improvement in the physicalcondition of the grain.

A further object of the present invention is to render the processaccurately controllable so that the desired percentage of moisture canbe removed with exactness so as to avoid loss in weight beyond thatwhich is necessary to insure the grain against fermentation;

Methods heretofore pursued have generally proceeded upon the theory ofseparating the grain into comparatively thin bodies, through which theheating and drying medium can be readily forced with more or less rapidaction. Such processes, however, proceed upon an incorrect theory, forthe reason that they so localize or intensify the heating and dryingeffects either on the outer layers ofthe grain'or on one side only ofmany of the grains, that the effect is not uniform and as a consequencethe grain subsequently stored-in bulk may again become heated and causedto ferment or the surface is rendered dull, or parts of the brittle as'to become handling.

One feature of my present invention consists in handling the grain inbulk both in the preheater or preliminary drier and cooler, so that theefiects produced are necessarily distributed with great uniformitythroughout the individual grain as well as the entire body of the grain.

Another feature consists in moving the grain, while in bulk and duringthe heating broken in subsequent process, so that each individual grainprogresses slowly through the heater, constantly changing its position,as well as its direction rain are rendered so of-movement, and isrepeatedly brought with first one side and then the other against theheating surfaces, while it is. at all times so surrounded and closelypacked with the other grains that the heat is forced to penetrate eachgrain uniformly until it emerges from the heater or reaches the end ofthe heating stage; In this way, while there is driven off a considerableproportion of the moisture sweatedout of the grain, as a result of therising temperature of its contained moisture,the surface of the grainis-not dried out to retard escape of the innermost moisture as where thegrain issubjected in thin layers to a hot blast. In my process, thepores of the grain remain open for the escape of the moisture in thesubsequent stages of theprocess. Moreover, the bran or skin of the grainis not rendered dull in appearance or brittle.

Some kinds of grain and particularly corn are extremely hard topenetrate in the vaporizi action; that is to say, moisture contained 1nthe innermost parts is very difficultto vaporize and drive out. Thiscondition not only increases the difiiculty. of getting satisfactoryresults with old rocesses, but greatly adds to the expense of operationif the application of the-heating mediumis to be-continued until thegrain becomes thoroughly soaked.

Another feature of my invention consists.

in confining the grain, still in bulk, after the preheating andpreliminary drying action above described, and permitting it to con-.tinue the heating efiect and even raisin its own inherent temperatureafter it has een removed from the influence of the artificial heatingmedium or after the latter has been cut off; this step in the treatmentcontinuing until the grain is thoroughly soaked throughout and all partshave their moisture vaporized and seeking exit through the structure ofthe grain. Here again the confinement of the grain in bulk acts not onlyto favor the process, but to maintain the conditions of surface porosityalready referred to which insure the desired ends of uniform treatmentand subsequent conditions of marketability. This self-heating orconditioning of the grain being continued for such periodas experienceshows to be suflicien-t, the grain is next subjected to the drying step.

The next feature of my invention, therefore, consists in drying andcooling the grain while still in bulk and while in condition parts ofthe grains. This introduces the element of time sufliciently to enablethe drying effect to be carried on to exactly the de. gree or percentagedesired, so that while on the one hand, the grain is thoroughlyconditioned against subsequent heating or fermentation, on the otherhand, it is not dried to a point of excessive loss in weight. Moreover,the .grain emerges from the drier with bright lustrous appearance,sufiiciently hard but not sufliciently brittle on the surface tofracture when being elevated or spouted into storage bins.

One form of apparatus suitable for carrying out the several steps of myprocess is illustrated in the accompanying drawing, in which Figiire 1is a vertical section through both the preheating portion and thesweatlng and COOlIDg portion of the apparatus; Fig. 2 is a verticalsection of the same, in a plane at right angles to Fig. 1; Fig. 3 is ahorizontal section on the line 3-3 of Figs. 1 and 2, and Fig. 4 is asection'on the line 4-4' of Figs. 1 and 2.

' The apparatus selected for illustration comprises a combinedpreheating and preliminarydrying section A, and a combined sweating andcooling section B. The section B is so related to the section A as toreceivethe grain therefrom either by gravity or some other approvedmeans of transfer.

The section A comprises a preheating chamber 1 surrounded by flues 2 fortaking oil moist air and having arranged transversely therein heatingpipes 3 for preheating the grain. Pipes 3 are arranged in horizontalseries, one series above another and with the pipes of adjacent seriesstaggered.- or alternated in position so as to develop among the pipes,a series of zig-zag passageways for the grain. The walls 4 of thechamber 1 are provided at intervals with guard plates 5 overlying airvents 6 and inclined downwardly and inwardly so as to serve the combinedpurpose of deflecting the grain inward toward the pipes and preventingthe escape of the grain through the vents, while leaving said vents openfor the escape of air. Certain of the pipes 3, for instance centraltriangular groups 3 at different vertical intervals, are provided withinverted V-shaped troughs 7 which extend between and through oppositeend walls of the chamber 1 so as to provide esca e passages for themoist air from the mid le ortion of the chamber. The bottom of t echamber 1 is made up of a series of cut-ofi' slides 8 for controllingthe escape of the grain into the hopper 9, through which it 1s deliveredto the section B. Each of thepipes 3 is tapped at its ends into theexpansion chamber 10 of the manifold castings 11-, while within eachpipe 3, is a steam pipe 12 which taps into the steam chambers 13 of thecastings 11. Steam supply ipe 14.- and steam outlet 15, suitablyconnected to the castings, are adapted to keep up a steam circulationthrough the heating pipes of such temperature as may be desired andpredetermined by suitable control of steam valves. i The section Bcomprises essentially a chamber in which to permit the grain to stand asufiicient time to sweat or permit the heat to soak thoroughly throughit after leaving the preheating chamber; also means for subsequentlycooling the grain and carrying oif its evaporated moisture, which may beapplied either to the same chamber as that in which the sweating takesplace or a separate chamber to which the grain is delivered from thesweating chamber. For convenience in conducting the process continuouslyand treating one batch of grain after another, the section B isconstructed with a receiving chamber 16 which the enters from the hopper9; a sweating c amber 17 in which a given quantity of ain can be storedand confined under condltions which cause it to heat; and a coolingchamber 18 having air stacks 19 supplied through an'air trunk 20 fromany suitable source of dry air, such for instance as a fan21. The

air stacks 19 are preferably provided with j tight covers 22, but havetheir walls constructed of reticulated material 23 so that the air canescape freely over the entire lower area of the body of grain in thechamber 18, so as to rise uniformly through the j entire body of grainand affect the entire body alike. The walls of the chamber 18,particularly above the body of grain, are provided with vents 24communicating with the air flues 25 and extend upwardly on all foursides of the section B and communicate through flues 26 with the flues 2surrounding the section A. The warm moist air from both the section Aand the. chamber 18 of the section B escapes through a stack 27.

In order to have in the chambers 17 and 18, a body of grain ofsubstantially uniform vertical dimensions throughout its area, thebottom of the chamber in each instance is formed with inclined surfacessubstantially parallel to the natural inclination developed by theflowing of the grain as it enters the chamber. Thus the bottoms arealternately inclined upwardly and downwardly from the middle point. Thedownwardly inclined bottom for the chamber 18 and the upwardly inclinedbottom for the sweating chamber 17 are preferred, because thisarrangement leaves substantial air surfaces above the body of grain inthe chamber 18 through which to provide escape for the moist air risingfrom the body of grain. This, hw-

ever, is a matter of convenience rather than essential.

In carrying out the process, the chamber 1 is fed with grain which flowsslowly through the circuitous passageways among the staggered pipes, sothat the grain flows first in one direction and then in the-other,bringing first one side of the grain and then the other against thepipes, so that it is heated uniformly. The chamber being filled duringthis flow, the grain is always in bulk and its moisture is preventedfrom being dissipated suddenly or locally on any particular part of thegrain or on the exterior of the grain more rapidly than the moisture canpass outward from the interior. In this way, skin drying or overheatingof the surface of the gram is avoided and when the grain escapes throughthe hopper 9, it is in a superior condition with the contained moistureremaining in the grain uniformly distributed therein, with the surfaceof the grain bright and not parched or dried out. A certain proportionof the moisture will have been withdrawn from the grain through thevents 6 and inverted troughs 7 and the grain will be thoroughly anduniformly heated to about 17 0 F. As the preheating and preliminarydrying step which takes place in section A involves a slow and gradualfeed of the grain, the chamber 16 will be employed to receive thedischarged grain until a sufiicient charge or quantity for sweating hasbeen accumulated, orsaid grain will beallowed to pass immediatelythrough the chamber 16 into the chamber 17, until the latter is filled,after which valves 28 will be closed and the self-heating or sweating ofthe grain in theclosed chamber 17 will be allowed to proceed, say forone and one-half hours, while the slowly advancing grain from thesection A will be allowed to accumulate in the chamber 16 ready for thenext charge. After the grain has been sufficiently sweated, the coolingand final drying step in the process is introduced. This obviously couldbe carried on in the chamber 17 by opening suitable air circulatingpassages, but in order to have the cooling of one charge proceedingwhile the next charge is sweating, the grain is discharged through thevalve 29, from chamber 17 into chamber 18, whereupon a gentle supply ofdry air is delivered through the stacks 22 in a manner to permeate theentire lower stratum of the grain and said air is allowed to risethrough the body of grain mainly by its levity resulting from theacquired heat and to escape through theair ports 24 into the fiues 25.Here again the too rapid drying of the grain on the outside is'avoidedwith the result that the thoroughly and uniformly sweated grain can giveoff its entire-moisture to be removed, as the moisture is taken up bythe air. The grain will issue from the chamber 18 through fines 30 intothe hopper 31 and spout 32 to storage with just the amount of moisturedesired, with a lustrous skin surface, without brittleness that inducesbreaking of the grain and thoroughly conditioned for storage or shipmentin'warm climates. The slowness with which the cooling takes place andthe retention of the grain in bulk during this step enable the degree ofmoisture to be determined to a nicety and insure the uniform treatmentof the .entire body of grain as well as the physical condition of thegrain when the process is complete. The percentage of moisture to bedriven out of the grain will vary greatly according to the character ofthe grain and the amount of natural evaporation that has taken lace.Corn may under some extreme conditions have as much 24% of moisture andthis may decrease down to 16%, whereas not more than of moisture shouldbe present in the .grain to insure its keeping in good condition in awarm climate. If 24% of moisture is contained in the corn, it mayrequire as much as one and one-half hours treatment in the slowdryingstep of the process. If, however, only 1, 2 or 3% of moisture isto be removed, the time required in the cooler will be proportionatelyless. About minutes will ordinarily be required to thoroughly heat thegrain in the preheater without injuring it. Hence, it will be seen thatthe grain passes slowly through the preheater, and it is quitepracticable to arrange the subsequent stages of the process so that onecharge can be cooled while other charges are being heated and sweated.

Any suitable mechanical means may be employed for gradually anduniformly discharging the grain into the hopper 9 in order to insure itsuniform progress through the preheater.

I claim:

1. The process of. drying grain which consists in preheating the grain,closely confining the preheated grain in bulk, and sweating it by itspreviously added heat and then slowly cooling and drying it by passingthrough the grain a cooling medium capable of taking up moisture.

2. The process of drying grain which consists in preheating the grainwhile in bulk with the grains closely associated, then ,closelyconfining the preheated grain in bulk and sweating it by its containedheat, and then slowly cooling and drying the grain by assing through-ita. cooling medi-' um ca ab e of takin up its moisture.

3. T e process of rymg grain which consists in preheating the grain,closely con- 5 fining the preheated gram and sweating it by itscontained heat, then delivering uniformly throughout the bottom of thebody of grain, a cooling and drying medium and permitting said medium torise through the meager body oi grain as it-rtakes up the heat from 10the grain.

Theforegoing specification signed at Washington, Dlstrict of Columbia,this 28th day of August, .1912.

' LEE J. DENNIS. In presence of two witnesses: Hnnvny S. KNIGHT,

BENNETT S. J onus.

